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À l’occasion d’une fouille dans la vallée de l’Escaut, une étude géomorphologique a permis, à partir de données nouvelles, de mieux appréhender la dynamique sédimentaire de la rivière au cours de l’Holocène inférieur. Ces données montrent qu’un environnement fluvio-lacustre s’installe à la transition Weichsélien/Holocène et disparaît avec la densification des forêts de pins. Elles participent probablement à l’abaissement de la nappe phréatique, mais également à l’augmentation de la fréquence et de l’étendue des feux de forêt naturels amenant à une période d’instabilité des versants et à un accroissement de la dynamique alluviale. L’apparition des forêts mixtes moins sujettes aux feux entraine l’extension des marécages alluviaux. During an archaeological excavation in the Scheldt Valley, a geomorphological study allowed a better understanding of the sedimentary dynamics during the Early Holocene. The data provide evidence of a fluvio-lacustrine environment established at the Weichselian/Holocene transition which disappeared with the intensification of pine forests. The latter probably contributed to the lowering of groundwater, but also to the increase in the frequency and extent of natural forest fires leading to a period of slope instability and a renewal of alluvial dynamics. The emergence of mixed forests less prone to fires ultimately leads to the formation of alluvial swamps.

Dit rapport werd ingediend bij het agentschap samen met een aantal afzonderlijke digitale bijlagen. Een aantal van deze bijlagen zijn niet inbegrepen in dit pdf document en zijn niet online beschikbaar. Sommige bijlagen (grondplannen, foto’s, spoorbeschrijvingen, enz.) kunnen van belang zijn voor een betere lezing en interpretatie van dit rapport. Indien u deze bijlagen wenst te raadplegen kan u daarvoor contact opnemen met: bib.oe@vlaanderen.be

En archéologie comme dans les études paléoenvironnementales, la phase de terrain est essentielle, car elle constitue la collecte des données et du matériel qui vont servir aux études en laboratoire. Cette étape est d'autant plus délicate en contexte préventif que le temps est un facteur clé. La méthodologie employée lors des fouilles préventives du site de Kerkhove Stuw a permis une étude paléoenvironnementale approfondie, apportant de nouvelles informations sur l’évolution du paysage de la vallée de l’Escaut depuis la fin du Weichsélien., This article is part of a book edited at the occasion of the Geoarchaeological meeting of Bruges: Soils as records of Past and Present: the geoarchaeological approach. Focus on: is there time for fieldwork today? - Bruges (Belgium), 6 and 7.11.2019. Editors Judit Deák, Carole Ampe and Jari Hinsch Mikkelsen Technical editor Mariebelle Deceuninck English language reviewer Caroline Landsheere Graphic design Frederick Moyaert Printing and binding Die Keure, Bruges

Prior to the excavations at Kerkhove-Stuw, carried out in 2015-2016 by GATE bvba and Ghent University, data gathered through manual and mechanical coring demonstrated the presence of Mesolithic occupations on the top of a Late Glacial levee, adjacent to a palaeochannel of the river Scheldt. The presence of thick packets of Holocene peat and alluvial deposits on top of the levee indicated good preservation conditions for both the archaeological and environmental remains. Subsequent excavations over a surface of ca . 4000 m² led to the discovery of thirteen lithic concentrations dating from the early to the late Mesolithic, which were all fully exca-vated. The first 14C-dates on burnt hazelnut shells, however, suggest that the main occupation took place in the first half of the Boreal. Within these clusters, nine possible surface hearths could be derived from the spatial clustering of severely burnt lithic and organic residu, e.g. burnt hazelnut shells and calcined bone fragments. Besides lithics and burnt/charred organic remains, the site exceptionally yielded unburnt faunal remains. Despite their fragmentation, the analysis demonstrates the dominance of roe deer and wild boar, next to fur animals and numerous fish remains. High-resolution multi-proxy palaeoenvironmental research mainly focused on the channel infilling, which consists of calcareous gyttja covered by peat. According to the first results, sedimentation started in the Late Glacial (probably Younger Dryas) and continued during the Early to Middle Holocene. During the Mesolithic occupations the Scheldt seemingly was already reduced to a shallow, slow running stream, however with an abundant riparian vegetation. The latter was exploited by Mesolithic hunter-gatherers for tool production (basketry, nets, ropes, etc .), as indicated by the wear traces on numerous flint tools.

The sedimentary evolution of the alluvial plain of the lower River Scheldt between Wetteren and Dendermonde, was studied based on more than 1000 hand borings, radiocarbon, dendrochronological and OSL dating, palynological analysis and archaeological surveys. The results show a laterally migrating river during the Late Glacial, creating large meander loops. During the Late Dryas fluvial processes interacted with aeolian processes, resulting in dune formation. During the early Holocene, fluvial activity diminished resulting in an underfit river in which vertical accretion became the dominant fluvial process. The presence of multiple small channels in some parts of the study area demonstrates that the fluvial system evolved locally to an anabranching river. Meanwhile vertical accretion continued. Short before the Roman period, the River Scheldt returned to a distinct single-channelled meandering pattern. As lateral migration was limited vertical accumulation processes continued to dominate the fluvial environment. This process was halted by the construction of an extensive network of dikes from the medieval period onwards.

A chitinozoan biozonation is established for the Upper Ordovician rocks of the Sennette valley in the Fauquez area and the Asquempont area, revising the existing chitinozoan biozonation of the Brabant Massif. The chitinozoans of five formations (the Ittre, Bornival, Huet, Fauquez and Madot formations) are studied from 70 samples. The chitinozoan biozonation is correlated with Baltoscandia and the Avalonian Upper Ordovician type sections in the U.K. This correlation provides an accurate dating of the studied formations. A megaslumping event, affecting a part of the Ittre and Bornival Formation and causing the overturning of a pile of sediments estimated at minimum 200 m thick, may be placed in the mid Oandu (Cheneyan, middle Caradoc, early Stage 6"?). The volcanic rocks in the Fauquez area, formally thought to be restricted to the Ashgill, are confined to the late Caradoc - early Ashgill timespan. In addition to this, this paper presents new lithostratigraphical data on the Ittre Formation and the lower member of the Bornival Formation.

ispartof: Geologica Belgica vol:8 issue:4 pages:145-159 status: published